Thread (5 messages) 5 messages, 2 authors, 2017-09-06

[Question] PCI ACS is broken for ARM SMMU v3?

From: wangzhou1@hisilicon.com (Zhou Wang)
Date: 2017-09-04 12:33:22
Also in: linux-pci

+to: Lorenzo

On 2017/8/31 22:21, Zhou Wang wrote:
Hi Will and Alex,

pci_request_acs is called in drivers/iommu/arm-smmu-v3.c to set pci_acs_enable.

PCI subsystem tries to enable ACS as below:

	pci_device_add
		--> pci_init_capabilities
			--> pci_enable_acs

in ACPI PCI driver. However, ACPI PCI driver will be called before SMMU v3 driver,
which will lead pci_enable_acs to return directly as pci_acs_enable is not set
before SMMU v3 driver loading.

I think this is a bug, what do you think about this problem?

Best,
Zhou





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